The invention pertains to a facility for the pneumatic manufacture/discharge of concrete that is hydromechanically transported in a dense flow.
Such a device is already known from U.S. Pat. No. 5,066,203. The discharge device described there is provided with a concrete pump for the hydromechanical transport, that is operated with a hydraulic drive of at least two opposed pistons. The Pump is synchronized (controlled to deliver a constant flow) by a displacement circuit. Additionally, the known device contains a dosing device for a solidification accelerator. The drive of the dosing device is installed in the hydraulic circuit of the pump drive and designed as a linear piston drive. The intake volume of the linear piston drive corresponds to the displacement volume of the working piston of the displacement circuit. A linear piston pump serves as the dosing device, where the linear piston drive and the linear piston pump are connected with each other and a slide is provided at the connection of drive and pump. In addition, a distributing valve for the redirection control of the solidification accelerator flow is installed in the discharge line of the dosing device to a solidification accelerator tank or into the additive discharge line, where the valve is subjected to the prevailing pressure of the hydraulic medium in the piston cavity of the working cylinder.
The known device with the solidification accelerator dosing device delivers already good results in practical application in the discharge of concrete. With the aid of the slide between linear piston drive and linear piston pump, the ratio between the volumes of the solidification accelerator and the concrete flow volume may be adjusted in a range from a minimum to a maximum value.
However, it was found that it occurs frequently in applications that, for various reasons, in addition to the solidification accelerator simultaneously another additive or dosing agent must be added to the concrete to be generated, and that it is necessary to add the solidification accelerator, and also other additives or dosing agents, in a range from a minimum to a maximum amount.